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  • 简介:Mammaliantoothdevelopmentislargelydependentonsequentialandreciprocalepithelial-mesenchymalinteractions.Theseprocessesinvolveaseriesofinductiveandpermissiveinteractionsthatresultinthedetermination,differentiation,andorganizationofodontogenictissues.Multiplesignalingmolecules,includingBMPs,FGFs,Shh,andWntproteins,havebeenimplicatedinmediatingthesetissueinteractions.Transcriptionfactorsparticipateinepithelial-mesenchymalinteractionsvialinkingthesignalingloopsbetweentissuelayersbyrespondingtoinductivesignalsandregulatingtheexpressionofothersignalingmolecules.Adultstemcellsarehighlyplasticandmultipotent.Thesecellsincludingdentalpulpstemcellsandbonemarrowstromalcellscouldbereprogrammedintoodontogenicfateandparticipatedintoothformation.Recentprogressinthestudiesofmolecularbasisoftoothdevelopment,adultstemcellbiology,andregenerationwillprovidefundamentalknowledgefortherealizationofhumantoothregenerationinthenearfuture.

  • 标签: 干细胞 转录因子 生长因子 哺乳动物 牙齿 发育
  • 作者: 周龙芹
  • 学科: 文化科学 > 教育学
  • 创建时间:2012-06-16
  • 出处:《中学课程辅导:教师教育》 2012年第6期
  • 机构:作者简介:周龙芹,陕西师范大学在读教育硕士,西安高级中学英语教师。从事中学英语教学工作13年。曾多次荣获全国英语教师教学技能大赛陕西赛区一、二等奖;曾被西安市教育局授予“五四青年标兵”称号;也曾多次获得西安高级中学优秀教师及优秀班主任的荣誉。2010年被国家留学基金委西部项目录取远赴英国里丁大学进修学习。
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  • 简介:Productinnovationisoftendescribedasthe'lifeblood'ofacompany.Justlikebloodthatflowsthroughthehumanbody,productinnovationprovidessustenanceandthebasisforgrowth.Butproductinnovationisverychallengingformostcompanies.Thecostsinvolvedandtheriskoffailurearehigh.Researchindicatesnewproductfailureratesof

  • 标签: 人才市场 人力资源管理 人才培养 培训方法
  • 简介:AbstractPurpose:The use of tourniquet in orthopedic surgery facilitates operation by establishing a bloodless surgical field. However, many complications following the use of tourniquets have been reported. Tourniquet pain is the most common complication. This study aimed to find the actual incidence of pain associated with tourniquet use in orthopedic surgery and the various factors.Methods:It is a prospective observational study conducted on 132 consecutive cases. Patients aged 18-70 years with musculoskeletal problems of the forearm and leg requiring surgery were included in the study. Patients with open injuries or contraindications such as diabetes mellitus, compromised circulatory states, neurological deficit, compartment syndrome and unable to give informed consent were excluded. The parameters assessed included duration of tourniquet use, tourniquet pressure, type of anesthesia, any interval release of the tourniquet and reapplication after a reperfusion period, whether upper or lower limb surgery, severity of tourniquet pain, timing of tourniquet release and complications. Chi-square and non-parametric Mann-Whitney U test were used for data analysis.Results:In upper limb surgeries, if duration of surgery was less than 60 min, 14 (51.8%) cases experienced tourniquet pain and 13 (48.1%) had no pain, and if duration of surgery was more than 60 min, 24 (60.0%) had pain and 16 (40.0%) experienced no pain. In lower limb surgeries if duration of surgery was less than 60 min, 2 (7.7%) experienced pain and 24 (92.3%) had no pain, and if duration of surgery was more than 60 min, 14 (35.8%) experienced pain and 25 (64.8%) had no pain. Degree of tourniquet pain increases with the duration of surgery. Statistically, there was significant association between tourniquet inflation time and tourniquet pain in both upper and lower limbs (p = 0.034 and 0.024, respectively)Conclusion:Incidence of tourniquet pain was in direct proportion to the duration of tourniquet use and was higher in cases with regional anesthesia. Other risk factors assessed including tourniquet pressure, upper or lower limb surgery, tourniquet release time and interval had no significant contribution to the incidence or severity of tourniquet pain.

  • 标签: Tourniquet pain Pneumatic tourniquet Bloodless field Orthopedic surgery Complications Pain intensity
  • 简介:Thecorneahasuniquefeaturesthatmakeitausefulmodelforregenerativemedicinestudies.Itisanavascular,transparent,denselyinnervatedtissueandanypathologicalchangescanbeeasilydetectedbyslitlampexamination.Cornealsensitivityisprovidedbytheophthalmicbranchofthetrigeminalnervethatelicitsprotectivereflexessuchasblinkingandtearingandexertstrophicsupportbyreleasingneuromediatorsandgrowthfactors.Cornealnervesareeasilyevaluatedforbothfunctionandmorphologyusingstandardinstrumentssuchascornealesthesiometerandinvivoconfocalmicroscope.Alllocalandsystemicconditionsthatareassociatedwithdamageofthetrigeminalnervecausethedevelopmentofneurotrophickeratitis,araredegenerativedisease.Neurotrophickeratitisischaracterizedbyimpairmentofcornealsensitivityassociatedwithdevelopmentofpersistentepithelialdefectsthatmayprogresstocornealulcer,meltingandperforation.Currentneurotrophickeratitistreatmentsaimatsupportingcornealhealingandpreventingprogressionofcornealdamage.Novelcompoundsabletostimulatecornealnerverecoveryareinadvanceddevelopmentstage.Amongthem,nervegrowthfactoreyedropsshowedtobesafeandeffectiveinstimulatingcornealhealingandimprovingcornealsensitivityinpatientswithneurotrophickeratitis.Neurotrophickeratitisrepresentsanusefulmodeltoevaluateinclinicalpracticenovelneuro-regenerativedrugs.

  • 标签: 神经再生 神经营养 因子和 神经生长因子 全身性疾病 角膜炎
  • 简介:-Byusinggas-liquidtwo-phaseflowtheory,amodifiedmathematicalmodelbasedonthecomputationalfluiddynamicsmethodSIMPLE(Semi-ImplicitMethodforPressure-LinkedEquations)isintroducedtoinvestigateimplosionphenomenainhighpressurechamberssystematically.Atheoreticalsimulation-predictionmethod,whichisindependentofexperimentaldata,isdevelopedinthepaperandgreatimprovementhasbeenmadeonthetopic.Inthepaper,variousimplosionsituationshavebeensimulatedandpredicted.Effectsofaseriesoffactorsinfluencingimplosionresultsandmethodsofreducingimplosiondangerhavebeenanalysed.Theanalysisresultsareofimportancetounderwaterengineeringpractice.

  • 标签: IMPLOSION TWO-PHASE FLOW IMPLOSION pressure NUMERICAL
  • 简介:Asiswellknown,somepeoplearemoresuccessfulthanothersinlearning.Thisdifferentlevelsofachievementmaybeattributedtovariablesassociatedwiththelearner.Inrecentyearstherehasbeenextensiveresearchintoaspectsofdifferencesinlearningasecondlanguage.Thispaperbrieflyreviewsanddiscussesthemajorparametersofthedifferencesamongindividu-alswhichresearchstudiesindicatemayinfluencethesuccessofsecondlanguagelearning,citingsixareasofinterest:age,intel-ligence,cognitivestyles,personality,motivationandattitude.

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